The present invention relates to ink-jet printing systems, and more particularly, ink-jet printing systems which make use of ink containers that are replaceable separate from a printhead.
Ink-jet printers frequently make use of an ink-jet printhead mounted to a carriage which is moved back and fourth across a print media, such as paper. As the printhead is moved across the print media, a control system activates the printhead to deposit ink droplets onto the print media to form images and text.
Previously used printers have made use of an ink container that is separably replaceable from the printhead. When the ink cartridge is exhausted the ink cartridge is removed and replaced with a new ink container. The use of replaceable ink containers that are separate from the printhead allow users to replace the ink container without replacing the printhead. The printhead is then replaced at or near the end of printhead life and not when the ink container is exhausted.
Previously used off-axis ink delivery systems have made use of a memory device located in the ink container for altering the printhead drive conditions based on the information stored in the memory device. For example, U.S. Pat. 5,506,611 to Ujita et al discloses the use of a memory device having electric terminals for providing drive conditions to the printhead. These drive conditions include drive voltage, pulse width, frequency, and the number of preliminary discharges. The memory device is mounted to the outer surface of the ink cartridge so that electrical contacts for the memory device are spaced apart on the outer surface of the ink cartridge. As the ink cartridge is inserted into the ink-jet printer, electric terminals associated with the bubble-jet printer contact the electric terminals associated with the ink cartridge.
It is important that the ink container and printer form proper electrical connection to ensure proper printer operation. Proper electrical connection requires that each electrical contact associated with the ink container be electrically connected to a corresponding electrical contact associated with the printer portion. In addition, each of these electrical connections should be a reliable low resistance electrical connection.
One problem associated with the use of electrical contacts or terminals positioned on the outer portion of the ink cartridge is that these electrical contacts are subject to contamination. Contamination can result from the handling of the ink cartridge or ink spillage from the fluid interconnect. Contamination from handling includes hand oils and salts which are frequently present in human skin. This contamination may be transferred to the electrical contacts associated with the printer. One particular contamination problem is the combination of dust and hand oils. Contamination of the electrical contacts can result in unreliable electrical contact between the ink cartridge and the printer resulting in system reliability problems. Furthermore, the use of electrical contacts on the outer surface of the ink cartridge makes these terminals susceptible to liquid contamination such as moisture or spilled ink. Liquid contaminates can result in the shorting of these electrical contacts resulting in a faulty electrical interconnect and possibly system failure. Furthermore, inks used for ink-jet printing typically make use of solvents and surfactants which over time can result in corrosion of the electrical contacts preventing proper electrical contact between the printer and ink container.
Another problem associated with the use of electrical contacts or terminals positioned on the outer portion of the ink cartridge is that these contacts are subject to mechanical damage to the contacts such as scraping, denting or pealing, to name a few. This damage, if sufficient, may result in reliability problems or failure of the electrical interconnect between the printer and ink container.
Still another problem associated with the use of electrical terminals positioned on the outer portion of the ink cartridge is that these terminals subject the storage device to electrostatic discharge (ESD). Electrostatic discharge results from the electric terminals contacting a charged surface resulting in a discharge through the storage device. This discharge can result in catastrophic failure or reduce lifetime or reliability of the storage device. Storage devices such as CMOS semiconductor devices are particularly susceptible to electrostatic discharge damage.
There is an ever present need for printing systems which are capable of providing low operating costs such as printers which make use of off-axis type ink supplies. In addition, these printing systems should be easy to operate, such as, including some form of memory for storing printing parameters so that the user is not required to adjust printer parameters when the ink container is replaced. These ink supplies should be capable of reliable insertion into the printing system to ensure proper fluid interconnection and proper electrical interconnection with the printer is achieved. In addition, these interconnections should be reliable and should not degrade over time and use. For example, the fluid interconnect should not leak during use or over time and the electrical interconnect should be reliable during use and over time. In addition, these ink cartridges should not require special handling by the user and should be reliable and easily connected by the user to form a positive highly reliable mechanical, electrical, and fluid interconnect with the printer.
These ink containment systems should be capable of providing ink at high flow rates to a printhead thereby allowing high throughput printing. This ink supply system should be cost effective to allow relatively low cost per page printing. In addition, the ink supply should be capable of providing ink at high flow rates in a reliable manner to the printhead.
Finally, electrical interconnection between the ink container and printer should be reliable without requiring relatively large contact force. The use of relatively large contact force tends to improve the reliability of the electrical interconnect. Large contact force interconnects tend to require increased latch and insertion forces which tend to result in increased costs due to higher force latch springs and larger latching surfaces. Therefore, the electrical interconnect should be capable of providing high reliability and requiring relatively low interconnect forces.